基于ACPT技术的纳米振动测量激光干涉仪

Laser Interferometer Based on ACPT Technique for Nanometer Vibration Measurement

为实现高精度、高稳定的微小振动测量,设计了一种改进型迈克尔逊干涉仪,对其所采用的光学结构和解调算法进行了分析.信号解调方案基于载波调制和交流相位跟踪(ACPT)技术,相对应的光路采用双压电陶瓷(PZT)和准平面猫眼动镜以构成参考臂和测量臂,设计以改善信噪比、抑制低频干扰、增强系统稳定性、提高测量分辨力为目标.建立了纳米振动发生装置,搭建了振动信号测量系统,研究了激光干涉仪对振动信号的输出特性.实验结果表明,测量动态范围达到120 dB,信噪比高于40 dB,系统分辨力达到0.25 nm.该干涉仪可有效抑制诸如温度、湿度、压强、低频振动等带来的相位噪声的干扰,满足高精度、稳定、可靠的要求.

To achieve high precision and stability of the micro-vibration measurement,an improved Michelson interferometer was designed and its optical structure and demodulation algorithm were analyzed.The signal demodulation scheme was based on carrier modulation and alternating current phase tracking（ACPT） technique,and the corresponding optical structure,reference arm and measurement arm were made up of double PZTs and quasi-plane cat′s eye moving mirror.The design aimed at improving signal to noise ratio（SNR）,restraining low-frequency interference,enhancing system stability and advancing resolution of measurement.Nanometer vibration generation equipment and vibration signal measurement system were established and the output characteristic of vibration signal from the laser interferometer were studied.Results indicate that the measurement dynamic range is up to 120 dB,SNR is over 40 dB,and the resolution of measurement reaches 0.25 nm.The improved interferometer can restrain the phase noise interference effectively,which was brought about by temperature,humidity,pressure and low-frequency vibration,and achieves high-precision,stability and reliability.